今回は2026の階乗と計算を説明します。
2026の階乗は26504199827613667786970131079518572486199517697086570731742254038609529327178218283865461108531257020099819991576959776129378704824732601895675252383336237172919669541275443963663184380175319806034109972431295941718109738185812312078646546848433631183234887889205104435597791986972879061666325220527590851027159467193459049737136018690566863438226138307930587042489984746369737600479647580435877467663152893827217460936669404373076035690451079893124148676907874501060105917065683970193429830497172450342635812464000585776129912702465972401981140822124248150691744013696664640520663873763665701203657425573881434904303911136705954098112551954609416374851375047154940810725861150360949867712716284644491177929039571093125035757154091062132908923781410014985271992752155174408023083819299951534152193870017461241507099362914750011339165475543672449902696983413592565388457132456934160387274536289244344106956546516413267606305698181990633539330381929895367770477164565328509637315343314961181581203537323547414235037035200482156272718608469519442766176586599062299438509653460954570769363604253880325385624051107847570177247779574538364786675776553705077196481105148019955262480719787664454280330966019497347317237300674963654038069586040921376370335117165554900766424393569187454446634933012522575581933181587079962687756924552895363534876791352718984933125918110405203953638266775049421645467775511801076124681153691303312587261124329174664935094884528358177433674156440441218741142855564164628017022221521251903110263990627424331895189999346042664450394012183737276530469629201970595022958962521095000260803475602902039783088451862753385510678803469457777690578165907664409778872334795208692396701165712984575055664617774995989835112549174246021301074112879780090854199732528607100490325084440588261290156605638344704491878961370504429139278682691628973949078668376357613127069536957750021277537946276843209713000959684204280048594551213514546853931540459416817222457182959808445944115203164015018729325654556860459253331426004294684472822176867415042785703094881713632107352662000274587535986757787984792814117753082487978013694388085573328253827139469131877532539292975795825482418732150602445969978067869746369586933577420946271522132560290651959311187359061941139924985204111236097684465327509260414579346963875717298422001041162514043499794060427018130017420210895347433591630443810680309535549826971409394880418705948531394812763984407831689315479097487996005250854715014112833974976391727195943475296425893074517822986888701838934759759799014587076442492878132066535894698151719262514675026640039739117102243385045129518917364509226069261810257274376239482552391537073230921560063143916899348785852293953634560412183080925581597468515368419144521638270428488696779113007698366855123688550245830884979246431038910423627020686657492246349108418516887073821186228786413866157920310131052235593639748289831570969088055052648808060188887067500385215943899334645438207240876266969195670581990136805301247515865353406524114560466249193487225740343081509615901761015536678145891278427897333627596348168000846184970519063628754500797285000404016834422388799738311374791379199502588358656224726422530121607549560541438986700433715528743437311039894725048461348959486118351908841634615664650577711021353449827602501330803896469843737759265391632347553971645656696348935531277530849485998797550902994711599666877658052948040969330288393716725476466985759787107908089384553760885048649711942303930585486122114208978049983502121819600446953629994341476213386878602667273854820150452136314309809187206571759144598996035861721185885474130323870927288469914418172048546971801203900383196201618764048374532315954261609540802567154187165628915700451177356310778101910128383283192838073248263088661906779728463294121461664770209866636300604787309447480502306683555187238693305823434775710410830946362977971859231834280190196393187111588370312426851565331742553621815575545750156696426747700344972077988832388077932147701355944977618781402198630127126072419475530585294844774446031407323078269004168453399774264217204415933443832579663713256633223147363758876966758658648821341038682013999654226918082691975543907852482295729138854389299985913878568919426222527989168842848447615357648363395321115528214208202835541262254576857712592783368879093074952679067202431617108004181734744045289693991847663843261321457792670271330435900402307594082936610494427471943627211659442410454884217939827568419487440582691102887876919057014520250673816437847573756988708216573736095433957620447179121492220643561914274957232101879193099412632100588753010735828805195552440178761373084414637094356986713310979600378024337493636805026610403842072096664675735196964092035398897791890674803694075093359421868611967640611306071206740781340302965713861616274945283939942886739410341344034145770364021438844646817832916244069060887374529984355137153425254557429835198678718319883381978548121995017405727894191953042530152214891982764136200364500095649946994692863308360179109719996607466844429128344995753216089226281431753884385602762412656561918002423944135003942889554104260669864595945267206837575626248317656161297568472133864218179786355079196521281725330323394201517294761296620372635926820903804562415582219621620574880566392845313407545843384320000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000です。
この計算方法について紹介していきます。
階乗とは何か？
初めに、階乗とは何かを理解していきましょう。
階乗は、ある自然数nに対して、1からnまでの全ての数を掛け合わせたものになります。
つまり、nの階乗は、$n!=n(n-1)(n-2)…3\times2\times1$です。
※参考記事
[数A]階乗｜階乗とは、0の階乗が1になる理由も解説
2026の階乗
では、本題に入りましょう。
nの階乗の式に2026を代入して計算します。
$$n!=n(n-1)(n-2)…3\times2\times1$$
ここで$n=2026$とすると、下記のように計算できます。
$$2026!=2026\times2025\times2024\times2023\times2022\times2021\times2020\times2019\times2018\times2017\times2016\times2015\times2014\times2013\times2012\times2011\times2010\times2009\times2008\times2007\times2006\times2005\times2004\times2003\times2002\times2001\times2000\times1999\times1998\times1997\times1996\times1995\times1994\times1993\times1992\times1991\times1990\times1989\times1988\times1987\times1986\times1985\times1984\times1983\times1982\times1981\times1980\times1979\times1978\times1977\times1976\times1975\times1974\times1973\times1972\times1971\times1970\times1969\times1968\times1967\times1966\times1965\times1964\times1963\times1962\times1961\times1960\times1959\times1958\times1957\times1956\times1955\times1954\times1953\times1952\times1951\times1950\times1949\times1948\times1947\times1946\times1945\times1944\times1943\times1942\times1941\times1940\times1939\times1938\times1937\times1936\times1935\times1934\times1933\times1932\times1931\times1930\times1929\times1928\times1927\times1926\times1925\times1924\times1923\times1922\times1921\times1920\times1919\times1918\times1917\times1916\times1915\times1914\times1913\times1912\times1911\times1910\times1909\times1908\times1907\times1906\times1905\times1904\times1903\times1902\times1901\times1900\times1899\times1898\times1897\times1896\times1895\times1894\times1893\times1892\times1891\times1890\times1889\times1888\times1887\times1886\times1885\times1884\times1883\times1882\times1881\times1880\times1879\times1878\times1877\times1876\times1875\times1874\times1873\times1872\times1871\times1870\times1869\times1868\times1867\times1866\times1865\times1864\times1863\times1862\times1861\times1860\times1859\times1858\times1857\times1856\times1855\times1854\times1853\times1852\times1851\times1850\times1849\times1848\times1847\times1846\times1845\times1844\times1843\times1842\times1841\times1840\times1839\times1838\times1837\times1836\times1835\times1834\times1833\times1832\times1831\times1830\times1829\times1828\times1827\times1826\times1825\times1824\times1823\times1822\times1821\times1820\times1819\times1818\times1817\times1816\times1815\times1814\times1813\times1812\times1811\times1810\times1809\times1808\times1807\times1806\times1805\times1804\times1803\times1802\times1801\times1800\times1799\times1798\times1797\times1796\times1795\times1794\times1793\times1792\times1791\times1790\times1789\times1788\times1787\times1786\times1785\times1784\times1783\times1782\times1781\times1780\times1779\times1778\times1777\times1776\times1775\times1774\times1773\times1772\times1771\times1770\times1769\times1768\times1767\times1766\times1765\times1764\times1763\times1762\times1761\times1760\times1759\times1758\times1757\times1756\times1755\times1754\times1753\times1752\times1751\times1750\times1749\times1748\times1747\times1746\times1745\times1744\times1743\times1742\times1741\times1740\times1739\times1738\times1737\times1736\times1735\times1734\times1733\times1732\times1731\times1730\times1729\times1728\times1727\times1726\times1725\times1724\times1723\times1722\times1721\times1720\times1719\times1718\times1717\times1716\times1715\times1714\times1713\times1712\times1711\times1710\times1709\times1708\times1707\times1706\times1705\times1704\times1703\times1702\times1701\times1700\times1699\times1698\times1697\times1696\times1695\times1694\times1693\times1692\times1691\times1690\times1689\times1688\times1687\times1686\times1685\times1684\times1683\times1682\times1681\times1680\times1679\times1678\times1677\times1676\times1675\times1674\times1673\times1672\times1671\times1670\times1669\times1668\times1667\times1666\times1665\times1664\times1663\times1662\times1661\times1660\times1659\times1658\times1657\times1656\times1655\times1654\times1653\times1652\times1651\times1650\times1649\times1648\times1647\times1646\times1645\times1644\times1643\times1642\times1641\times1640\times1639\times1638\times1637\times1636\times1635\times1634\times1633\times1632\times1631\times1630\times1629\times1628\times1627\times1626\times1625\times1624\times1623\times1622\times1621\times1620\times1619\times1618\times1617\times1616\times1615\times1614\times1613\times1612\times1611\times1610\times1609\times1608\times1607\times1606\times1605\times1604\times1603\times1602\times1601\times1600\times1599\times1598\times1597\times1596\times1595\times1594\times1593\times1592\times1591\times1590\times1589\times1588\times1587\times1586\times1585\times1584\times1583\times1582\times1581\times1580\times1579\times1578\times1577\times1576\times1575\times1574\times1573\times1572\times1571\times1570\times1569\times1568\times1567\times1566\times1565\times1564\times1563\times1562\times1561\times1560\times1559\times1558\times1557\times1556\times1555\times1554\times1553\times1552\times1551\times1550\times1549\times1548\times1547\times1546\times1545\times1544\times1543\times1542\times1541\times1540\times1539\times1538\times1537\times1536\times1535\times1534\times1533\times1532\times1531\times1530\times1529\times1528\times1527\times1526\times1525\times1524\times1523\times1522\times1521\times1520\times1519\times1518\times1517\times1516\times1515\times1514\times1513\times1512\times1511\times1510\times1509\times1508\times1507\times1506\times1505\times1504\times1503\times1502\times1501\times1500\times1499\times1498\times1497\times1496\times1495\times1494\times1493\times1492\times1491\times1490\times1489\times1488\times1487\times1486\times1485\times1484\times1483\times1482\times1481\times1480\times1479\times1478\times1477\times1476\times1475\times1474\times1473\times1472\times1471\times1470\times1469\times1468\times1467\times1466\times1465\times1464\times1463\times1462\times1461\times1460\times1459\times1458\times1457\times1456\times1455\times1454\times1453\times1452\times1451\times1450\times1449\times1448\times1447\times1446\times1445\times1444\times1443\times1442\times1441\times1440\times1439\times1438\times1437\times1436\times1435\times1434\times1433\times1432\times1431\times1430\times1429\times1428\times1427\times1426\times1425\times1424\times1423\times1422\times1421\times1420\times1419\times1418\times1417\times1416\times1415\times1414\times1413\times1412\times1411\times1410\times1409\times1408\times1407\times1406\times1405\times1404\times1403\times1402\times1401\times1400\times1399\times1398\times1397\times1396\times1395\times1394\times1393\times1392\times1391\times1390\times1389\times1388\times1387\times1386\times1385\times1384\times1383\times1382\times1381\times1380\times1379\times1378\times1377\times1376\times1375\times1374\times1373\times1372\times1371\times1370\times1369\times1368\times1367\times1366\times1365\times1364\times1363\times1362\times1361\times1360\times1359\times1358\times1357\times1356\times1355\times1354\times1353\times1352\times1351\times1350\times1349\times1348\times1347\times1346\times1345\times1344\times1343\times1342\times1341\times1340\times1339\times1338\times1337\times1336\times1335\times1334\times1333\times1332\times1331\times1330\times1329\times1328\times1327\times1326\times1325\times1324\times1323\times1322\times1321\times1320\times1319\times1318\times1317\times1316\times1315\times1314\times1313\times1312\times1311\times1310\times1309\times1308\times1307\times1306\times1305\times1304\times1303\times1302\times1301\times1300\times1299\times1298\times1297\times1296\times1295\times1294\times1293\times1292\times1291\times1290\times1289\times1288\times1287\times1286\times1285\times1284\times1283\times1282\times1281\times1280\times1279\times1278\times1277\times1276\times1275\times1274\times1273\times1272\times1271\times1270\times1269\times1268\times1267\times1266\times1265\times1264\times1263\times1262\times1261\times1260\times1259\times1258\times1257\times1256\times1255\times1254\times1253\times1252\times1251\times1250\times1249\times1248\times1247\times1246\times1245\times1244\times1243\times1242\times1241\times1240\times1239\times1238\times1237\times1236\times1235\times1234\times1233\times1232\times1231\times1230\times1229\times1228\times1227\times1226\times1225\times1224\times1223\times1222\times1221\times1220\times1219\times1218\times1217\times1216\times1215\times1214\times1213\times1212\times1211\times1210\times1209\times1208\times1207\times1206\times1205\times1204\times1203\times1202\times1201\times1200\times1199\times1198\times1197\times1196\times1195\times1194\times1193\times1192\times1191\times1190\times1189\times1188\times1187\times1186\times1185\times1184\times1183\times1182\times1181\times1180\times1179\times1178\times1177\times1176\times1175\times1174\times1173\times1172\times1171\times1170\times1169\times1168\times1167\times1166\times1165\times1164\times1163\times1162\times1161\times1160\times1159\times1158\times1157\times1156\times1155\times1154\times1153\times1152\times1151\times1150\times1149\times1148\times1147\times1146\times1145\times1144\times1143\times1142\times1141\times1140\times1139\times1138\times1137\times1136\times1135\times1134\times1133\times1132\times1131\times1130\times1129\times1128\times1127\times1126\times1125\times1124\times1123\times1122\times1121\times1120\times1119\times1118\times1117\times1116\times1115\times1114\times1113\times1112\times1111\times1110\times1109\times1108\times1107\times1106\times1105\times1104\times1103\times1102\times1101\times1100\times1099\times1098\times1097\times1096\times1095\times1094\times1093\times1092\times1091\times1090\times1089\times1088\times1087\times1086\times1085\times1084\times1083\times1082\times1081\times1080\times1079\times1078\times1077\times1076\times1075\times1074\times1073\times1072\times1071\times1070\times1069\times1068\times1067\times1066\times1065\times1064\times1063\times1062\times1061\times1060\times1059\times1058\times1057\times1056\times1055\times1054\times1053\times1052\times1051\times1050\times1049\times1048\times1047\times1046\times1045\times1044\times1043\times1042\times1041\times1040\times1039\times1038\times1037\times1036\times1035\times1034\times1033\times1032\times1031\times1030\times1029\times1028\times1027\times1026\times1025\times1024\times1023\times1022\times1021\times1020\times1019\times1018\times1017\times1016\times1015\times1014\times1013\times1012\times1011\times1010\times1009\times1008\times1007\times1006\times1005\times1004\times1003\times1002\times1001\times1000\times999\times998\times997\times996\times995\times994\times993\times992\times991\times990\times989\times988\times987\times986\times985\times984\times983\times982\times981\times980\times979\times978\times977\times976\times975\times974\times973\times972\times971\times970\times969\times968\times967\times966\times965\times964\times963\times962\times961\times960\times959\times958\times957\times956\times955\times954\times953\times952\times951\times950\times949\times948\times947\times946\times945\times944\times943\times942\times941\times940\times939\times938\times937\times936\times935\times934\times933\times932\times931\times930\times929\times928\times927\times926\times925\times924\times923\times922\times921\times920\times919\times918\times917\times916\times915\times914\times913\times912\times911\times910\times909\times908\times907\times906\times905\times904\times903\times902\times901\times900\times899\times898\times897\times896\times895\times894\times893\times892\times891\times890\times889\times888\times887\times886\times885\times884\times883\times882\times881\times880\times879\times878\times877\times876\times875\times874\times873\times872\times871\times870\times869\times868\times867\times866\times865\times864\times863\times862\times861\times860\times859\times858\times857\times856\times855\times854\times853\times852\times851\times850\times849\times848\times847\times846\times845\times844\times843\times842\times841\times840\times839\times838\times837\times836\times835\times834\times833\times832\times831\times830\times829\times828\times827\times826\times825\times824\times823\times822\times821\times820\times819\times818\times817\times816\times815\times814\times813\times812\times811\times810\times809\times808\times807\times806\times805\times804\times803\times802\times801\times800\times799\times798\times797\times796\times795\times794\times793\times792\times791\times790\times789\times788\times787\times786\times785\times784\times783\times782\times781\times780\times779\times778\times777\times776\times775\times774\times773\times772\times771\times770\times769\times768\times767\times766\times765\times764\times763\times762\times761\times760\times759\times758\times757\times756\times755\times754\times753\times752\times751\times750\times749\times748\times747\times746\times745\times744\times743\times742\times741\times740\times739\times738\times737\times736\times735\times734\times733\times732\times731\times730\times729\times728\times727\times726\times725\times724\times723\times722\times721\times720\times719\times718\times717\times716\times715\times714\times713\times712\times711\times710\times709\times708\times707\times706\times705\times704\times703\times702\times701\times700\times699\times698\times697\times696\times695\times694\times693\times692\times691\times690\times689\times688\times687\times686\times685\times684\times683\times682\times681\times680\times679\times678\times677\times676\times675\times674\times673\times672\times671\times670\times669\times668\times667\times666\times665\times664\times663\times662\times661\times660\times659\times658\times657\times656\times655\times654\times653\times652\times651\times650\times649\times648\times647\times646\times645\times644\times643\times642\times641\times640\times639\times638\times637\times636\times635\times634\times633\times632\times631\times630\times629\times628\times627\times626\times625\times624\times623\times622\times621\times620\times619\times618\times617\times616\times615\times614\times613\times612\times611\times610\times609\times608\times607\times606\times605\times604\times603\times602\times601\times600\times599\times598\times597\times596\times595\times594\times593\times592\times591\times590\times589\times588\times587\times586\times585\times584\times583\times582\times581\times580\times579\times578\times577\times576\times575\times574\times573\times572\times571\times570\times569\times568\times567\times566\times565\times564\times563\times562\times561\times560\times559\times558\times557\times556\times555\times554\times553\times552\times551\times550\times549\times548\times547\times546\times545\times544\times543\times542\times541\times540\times539\times538\times537\times536\times535\times534\times533\times532\times531\times530\times529\times528\times527\times526\times525\times524\times523\times522\times521\times520\times519\times518\times517\times516\times515\times514\times513\times512\times511\times510\times509\times508\times507\times506\times505\times504\times503\times502\times501\times500\times499\times498\times497\times496\times495\times494\times493\times492\times491\times490\times489\times488\times487\times486\times485\times484\times483\times482\times481\times480\times479\times478\times477\times476\times475\times474\times473\times472\times471\times470\times469\times468\times467\times466\times465\times464\times463\times462\times461\times460\times459\times458\times457\times456\times455\times454\times453\times452\times451\times450\times449\times448\times447\times446\times445\times444\times443\times442\times441\times440\times439\times438\times437\times436\times435\times434\times433\times432\times431\times430\times429\times428\times427\times426\times425\times424\times423\times422\times421\times420\times419\times418\times417\times416\times415\times414\times413\times412\times411\times410\times409\times408\times407\times406\times405\times404\times403\times402\times401\times400\times399\times398\times397\times396\times395\times394\times393\times392\times391\times390\times389\times388\times387\times386\times385\times384\times383\times382\times381\times380\times379\times378\times377\times376\times375\times374\times373\times372\times371\times370\times369\times368\times367\times366\times365\times364\times363\times362\times361\times360\times359\times358\times357\times356\times355\times354\times353\times352\times351\times350\times349\times348\times347\times346\times345\times344\times343\times342\times341\times340\times339\times338\times337\times336\times335\times334\times333\times332\times331\times330\times329\times328\times327\times326\times325\times324\times323\times322\times321\times320\times319\times318\times317\times316\times315\times314\times313\times312\times311\times310\times309\times308\times307\times306\times305\times304\times303\times302\times301\times300\times299\times298\times297\times296\times295\times294\times293\times292\times291\times290\times289\times288\times287\times286\times285\times284\times283\times282\times281\times280\times279\times278\times277\times276\times275\times274\times273\times272\times271\times270\times269\times268\times267\times266\times265\times264\times263\times262\times261\times260\times259\times258\times257\times256\times255\times254\times253\times252\times251\times250\times249\times248\times247\times246\times245\times244\times243\times242\times241\times240\times239\times238\times237\times236\times235\times234\times233\times232\times231\times230\times229\times228\times227\times226\times225\times224\times223\times222\times221\times220\times219\times218\times217\times216\times215\times214\times213\times212\times211\times210\times209\times208\times207\times206\times205\times204\times203\times202\times201\times200\times199\times198\times197\times196\times195\times194\times193\times192\times191\times190\times189\times188\times187\times186\times185\times184\times183\times182\times181\times180\times179\times178\times177\times176\times175\times174\times173\times172\times171\times170\times169\times168\times167\times166\times165\times164\times163\times162\times161\times160\times159\times158\times157\times156\times155\times154\times153\times152\times151\times150\times149\times148\times147\times146\times145\times144\times143\times142\times141\times140\times139\times138\times137\times136\times135\times134\times133\times132\times131\times130\times129\times128\times127\times126\times125\times124\times123\times122\times121\times120\times119\times118\times117\times116\times115\times114\times113\times112\times111\times110\times109\times108\times107\times106\times105\times104\times103\times102\times101\times100\times99\times98\times97\times96\times95\times94\times93\times92\times91\times90\times89\times88\times87\times86\times85\times84\times83\times82\times81\times80\times79\times78\times77\times76\times75\times74\times73\times72\times71\times70\times69\times68\times67\times66\times65\times64\times63\times62\times61\times60\times59\times58\times57\times56\times55\times54\times53\times52\times51\times50\times49\times48\times47\times46\times45\times44\times43\times42\times41\times40\times39\times38\times37\times36\times35\times34\times33\times32\times31\times30\times29\times28\times27\times26\times25\times24\times23\times22\times21\times20\times19\times18\times17\times16\times15\times14\times13\times12\times11\times10\times9\times8\times7\times6\times5\times4\times3\times2\times1=26504199827613667786970131079518572486199517697086570731742254038609529327178218283865461108531257020099819991576959776129378704824732601895675252383336237172919669541275443963663184380175319806034109972431295941718109738185812312078646546848433631183234887889205104435597791986972879061666325220527590851027159467193459049737136018690566863438226138307930587042489984746369737600479647580435877467663152893827217460936669404373076035690451079893124148676907874501060105917065683970193429830497172450342635812464000585776129912702465972401981140822124248150691744013696664640520663873763665701203657425573881434904303911136705954098112551954609416374851375047154940810725861150360949867712716284644491177929039571093125035757154091062132908923781410014985271992752155174408023083819299951534152193870017461241507099362914750011339165475543672449902696983413592565388457132456934160387274536289244344106956546516413267606305698181990633539330381929895367770477164565328509637315343314961181581203537323547414235037035200482156272718608469519442766176586599062299438509653460954570769363604253880325385624051107847570177247779574538364786675776553705077196481105148019955262480719787664454280330966019497347317237300674963654038069586040921376370335117165554900766424393569187454446634933012522575581933181587079962687756924552895363534876791352718984933125918110405203953638266775049421645467775511801076124681153691303312587261124329174664935094884528358177433674156440441218741142855564164628017022221521251903110263990627424331895189999346042664450394012183737276530469629201970595022958962521095000260803475602902039783088451862753385510678803469457777690578165907664409778872334795208692396701165712984575055664617774995989835112549174246021301074112879780090854199732528607100490325084440588261290156605638344704491878961370504429139278682691628973949078668376357613127069536957750021277537946276843209713000959684204280048594551213514546853931540459416817222457182959808445944115203164015018729325654556860459253331426004294684472822176867415042785703094881713632107352662000274587535986757787984792814117753082487978013694388085573328253827139469131877532539292975795825482418732150602445969978067869746369586933577420946271522132560290651959311187359061941139924985204111236097684465327509260414579346963875717298422001041162514043499794060427018130017420210895347433591630443810680309535549826971409394880418705948531394812763984407831689315479097487996005250854715014112833974976391727195943475296425893074517822986888701838934759759799014587076442492878132066535894698151719262514675026640039739117102243385045129518917364509226069261810257274376239482552391537073230921560063143916899348785852293953634560412183080925581597468515368419144521638270428488696779113007698366855123688550245830884979246431038910423627020686657492246349108418516887073821186228786413866157920310131052235593639748289831570969088055052648808060188887067500385215943899334645438207240876266969195670581990136805301247515865353406524114560466249193487225740343081509615901761015536678145891278427897333627596348168000846184970519063628754500797285000404016834422388799738311374791379199502588358656224726422530121607549560541438986700433715528743437311039894725048461348959486118351908841634615664650577711021353449827602501330803896469843737759265391632347553971645656696348935531277530849485998797550902994711599666877658052948040969330288393716725476466985759787107908089384553760885048649711942303930585486122114208978049983502121819600446953629994341476213386878602667273854820150452136314309809187206571759144598996035861721185885474130323870927288469914418172048546971801203900383196201618764048374532315954261609540802567154187165628915700451177356310778101910128383283192838073248263088661906779728463294121461664770209866636300604787309447480502306683555187238693305823434775710410830946362977971859231834280190196393187111588370312426851565331742553621815575545750156696426747700344972077988832388077932147701355944977618781402198630127126072419475530585294844774446031407323078269004168453399774264217204415933443832579663713256633223147363758876966758658648821341038682013999654226918082691975543907852482295729138854389299985913878568919426222527989168842848447615357648363395321115528214208202835541262254576857712592783368879093074952679067202431617108004181734744045289693991847663843261321457792670271330435900402307594082936610494427471943627211659442410454884217939827568419487440582691102887876919057014520250673816437847573756988708216573736095433957620447179121492220643561914274957232101879193099412632100588753010735828805195552440178761373084414637094356986713310979600378024337493636805026610403842072096664675735196964092035398897791890674803694075093359421868611967640611306071206740781340302965713861616274945283939942886739410341344034145770364021438844646817832916244069060887374529984355137153425254557429835198678718319883381978548121995017405727894191953042530152214891982764136200364500095649946994692863308360179109719996607466844429128344995753216089226281431753884385602762412656561918002423944135003942889554104260669864595945267206837575626248317656161297568472133864218179786355079196521281725330323394201517294761296620372635926820903804562415582219621620574880566392845313407545843384320000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000$$
掛け算ができれば求まるので計算自体は難しくないですね。
nの値が大きい時は迷わず電卓やエクセルを使いましょう！
まとめ
ここまで読んでいただきありがとうございます。
2026の階乗を計算してきました。
nの階乗は、$n!=n(n-1)(n-2)…3\times2\times1$なので、nに代入すれば掛け算だけでも解けますね！
コメント